Wireless access systems have been widely deployed to provide various types of communication services such as voice or data. In general, a wireless access system is a multiple access system that supports communication of multiple users by sharing available system resources (a bandwidth, transmission power, etc.) among them. For example, multiple access systems include a Code Division Multiple Access (CDMA) system, a Frequency Division Multiple Access (FDMA) system, a Time Division Multiple Access (TDMA) system, an Orthogonal Frequency Division Multiple Access (OFDMA) system, and a Single Carrier Frequency Division Multiple Access (SC-FDMA) system.
Compared to legacy wireless access systems, a super-high frequency wireless access system operates with a center frequency of a few GHz to tens of GHz. The super-high frequency characteristics of the center frequency worsen the Doppler effect generated during movement of a User Equipment (UE) or the effects of a Carrier Frequency Offset (CFO) caused by an oscillator error between a UE and a Base Station (BS). For example, the Doppler effect and the CFO increase linearly with respect to the center frequency. The CFO resulting from the oscillator error between the UE and the BS has a large value in units of ppm (=10−6)
To overcome the CFO problem encountered with detection of a synchronization signal in a legacy cellular network, a BS transmits a Synchronization Channel (SCH), a pilot signal, and/or a Reference Symbol (RS) to a UE and the UE estimates and/or corrects a CFO using the received signal. However, the super-high frequency wireless access system generates a much larger CFO value than the legacy cellular network. Accordingly, there is a need for defining a synchronization signal/channel in a super-high frequency band and transmitting the synchronization signal/channel in a different manner from in a legacy network, in order to estimate/correct a CFO.